Microsoft Edge? Google's Project Zero team has released several details that help bypass an important security technique in Edge.
Let's see what the problem is:
Arbitrary Code Guard (ACG), released with the version of Windows 10 Creators Update to help prevent attacks from the web that attempt to load malicious code into memory. This technique ensures that the memory only accepts properly signed code.
However, as Microsoft explains, the Just-in-Time (JIT) compilers used in modern preletterweb browsers pose a problem for ACG. JIT compilers convert JavaScript into native code, which is not signed.
So to ensure that JIT compilers continue to run even when ACG is enabled, the company's developers split Microsoft Edge JIT into a separate process running on its own isolated sandbox.
But here came the researchers from Google's Project Zero. The researchers found that there is a problem in the way the JIT process writes executables data in the content.
THE 'bypass the ACG using UnmapViewofFileallows a content process to predict which address of a JIT process VirtualAllocEx () may call, as well as a content process that is preparing to "allocate a writable memory area to the same JIT server address for an executable to run soon" .
Google reported the issue to Microsoft in mid-November and released the details of the exploit yesterday, as the 90 days have passed.
Microsoft confirmed the ACG bypass at some point in Patch Tuesday, which was released in February. Apparently the company intended to fix the issue by then, but found it a bit "more complicated" than it initially thought.
So the solution for a secure Microsoft Edge is expected to be released with Patch Tuesday in March.
